Such hydraulic systems (see, for example, U.S. Pat. No. 7,055,317 B1) are known and being used in diverse embodiments for various applications. For example, they are applied in motor vehicles, especially for actuation of convertible tops. In this respect, DE 10344648 A1 is an example of the pertinent prior art.
Especially for hydraulic systems for the foregoing application, increasingly greater demands are being made on the structural size and the weight, to the effect that the installation space for the hydraulic aggregate, meaning the unit comprising the pressurized-fluid tank, the pressurized-fluid pump and the motor driving it, is becoming extremely restricted in an increasing number of cases, and the hydraulic system on the whole must have particularly lightweight construction. In some cases, and to a certain extent, the structural size—for given system power—can be reduced by increasing the operating pressure. In turn, however, sealing problems may result, especially in view of the fact that the temperature to which the hydraulic system is exposed in a motor vehicle may undergo very large fluctuations. Precisely for convertible tops, however, even the slightest leak of the system cannot be tolerated.